Mexiletine

Indications

INDICATIONS AND USAGE Mexiletine hydrochloride capsules, USP are indicated for the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that, in the judgment of the physician, are life-threatening. Because of the proarrhythmic effects of mexiletine, its use with lesser arrhythmias is generally not recommended. Treatment of patients with asymptomatic ventricular premature contractions should be avoided. Initiation of mexiletine treatment, as with other antiarrhythmic agents used to treat life-threatening arrhythmias, should be carried out in the hospital. Antiarrhythmic drugs have not been shown to enhance survival in patients with ventricular arrhythmias.

Dosage and administration (summary)

DOSAGE AND ADMINISTRATION The dosage of mexiletine hydrochloride must be individualized on the basis of response and tolerance, both of which are dose-related. Administration with food or antacid is recommended. Initiate mexiletine therapy with 200 mg every eight hours when rapid control of arrhythmia is not essential. A minimum of two to three days between dose adjustments is recommended. Dose may be adjusted in 50 or 100 mg increments up or down.

Contraindications

CONTRAINDICATIONS Mexiletine hydrochloride capsules are contraindicated in the presence of cardiogenic shock or preexisting second- or third-degree AV block (if no pacemaker is present).

Warnings and precautions

WARNINGS BOXED WARNING WARNINGS Mortality In the National Heart, Lung and Blood Institute’s Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multicentered, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction more than six days but less than two years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3%).

Storage and supply

HOW SUPPLIED Mexiletine hydrochloride capsules USP, 250 mg are white granular powder in a hard gelatin capsule with a green opaque cap and an orange opaque body, imprinted with "A29" on the cap and "250" on the body in black ink. They are supplied as follows: NDC 72162-1784-1 bottles of 100 with child-resistant closure.

Source: Mexiletine Hydrochloride (Mexiletine Hydrochloride) — US FDA prescribing information, 2024-10-18, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.